Back in 1976, when George Bush was head of the Central Intelligence Agency and in charge of preparing the annual National Intelligence Estimate, he stirred up a big brouhaha by going outside the government for a "second opinion" on the critical question of the Soviet Union's global strategy.

To the distinct discomfort of the professionals on the inside, Bush called in Harvard Prof. Richard Pipes, a Russian history scholar and close student of Soviet affairs. And Bush set up what came to be known as "Team B" with a mission to second-guess the findings of the official government estimators ("Team A").

The net effect was to introduce into the final report a much dimmer view of the Soviet Union's global strategy, of its military capabilities, of its designs for world hegemony and its willingness to resort to nuclear war in pursuit of its purposes.

Today George Bush sits in the vice president's office in the White House. And right across the street in the Executive Office Building, in an office with a splendid view of Washington landmarks, sits the same Prof. Pipes. He is not on the inside as a member of the National Security Council staff -- a member, you might say, of "Team A" with a view of Soviet intentions that, if anything, has grown grimmer over the ensuing four years.

Along with the rest of the Reagan NSC staff, Pipes is under tight wraps: no public pronouncements, everything for "background"; logs to be kept of all other-than-social telephone calls. But it is not hard to get a grasp of his current thinking from assorted recently published works, with a little unattributable instruction from the professor himself.

Pipes on the Soviet Union is a crash course well worth taking, if for no other reason than what it tells you about the Reagan team's taste in Sovietologists. Just how direct a hand he will have in policymaking is hard to say. Secretary of State Alexander Haig is plainly bent on making the State Department the be-all-and-end-all of foreign policy "formation." He will have Walter Stoessel, a former ambassador to Moscow and career-long Soviet expert, in the No. 3 job and, as his top man for policy planning, Paul Wolfowitz (another former member, incidentally, of "Team B").

Still, Pipes will be the reigning White House Soviet scholar, working for National Security Adviser Richard Allen, who will be reporting to the president through White House Counselor Ed Meese. One way or another, then, the thinking of Richard Pipes is pretty much assured a hearing.

What you find in his writings are the scholarly under-pinnings for much of what both Reagan and Haig have been saying about the Soviet hand in world terrorism and/or Moscow's master plan for world domination.

"The roots of Soviet terrorism, indeed of modern terrorism," Pipes wrote recently, date back to 1879, when an organization called "The People's Will" was created in a small Russian town, Lipetsk. This small band of political assassins, which, among other things, murdererd Czar Alexander II, Pipes argues, is the true "source of all modern terrorist groups, whether they be named the Tupamaros, the Baader-Meinhof group, the Weathermen, Red Bidgard or PLO,"

Today, Pipes maintains that the Soviet Union "encourages and employs terrorism because terrorism is a handy and relatively cheap weapon in their arsenal to destroy Western societies. We must expose its support of terrorism as widely as possible. . . . It must be made absolutely clear that these activities will no longer be tolerated.

On the broader question of Soviet designs, Pipes reaches far back into pre-Communist Russian history for his theory that military has always been the dominant element in Russian society.

"Militancy -- that is, a commitment to violence and coercion -- and its principal instrumentality, militarism," he wrote recently, "seems to me as central to Soviet communism as the pursuit of profit to societies with market-oriented economies."

In Commentary magazine last year, he argued in an article called "Soviet Global Strategy" that "Marxist-Leninism is by its very nature a militant doctine." It is also, he went on, "an international doctrine. The phases in the evolution of mankind are global in scope and cannot be contained (except transitionally) within the limits of the nation-state."

He sees Russia as historically expansionist, perpetually seeking to acquire new territory, which requires new buffers, which in turn must be assimilated, requiring yet more buffers, in an endless process. The Soviets, he insists, will not hesitate to use nuclear weapons, not as deterrent, or a treat -- but actually use them, as a part of global strategy. The ultimate aim -- indeed a necessity for the sucess of Marxist-Leninism -- is the destruction of capitalism.

Ronald Reagan, it could be argued, needs little encouragement in these beliefs. But anytime he's looking for intellectual and historical reinforcement, he will find it right across the street, in the office of Prof. Pipes.